As technology advances the overall size of electronic devices shrinks. For electronic devices small by nature, e.g., paging devices, advancing technology significantly increases capability and function. For example, sophisticated paging devices are now available in the form and size of a conventional wristwatch with significant memory storage and information display capabilities.
In one important area, however, size reduction provides limited additional advantage. The user interface, i.e., user-operated buttons, must remain at sufficient size to allow user manipulation of the electronic device. Thus, even where overall size is reduced and electronic capabilities are increased, e.g., a paging device integrated into the form of a wristwatch, user-operable buttons remain at least at a minimal size to support user manipulation. Control buttons must be sufficiently large to allow activation by the user's finger tip. Because of significant overall size reduction, the number of such user-operable buttons is severely limited.
In the case of paging devices, for example, early paging devices could display a paging message received, but upon receipt of the next paging message the previous paging message was lost for lack of storage capability. Soon, however, paging devices stored several of the most recently received paging messages. Due to storage capacity limitations, however, only a limited number of paging messages could be stored. The user could review the stored messages as a simple list of items. For such a simple information structure, i.e., a limited number of items stored as a serial list, a limited number of control buttons allowed user manipulation of the paging device to review the stored paging messages. For example, pressing a single control button while in a display mode moves the display to the next item in the relatively small serial list of stored paging messages.
As paging technology advances, however, paging devices have acquired significantly greater storage capabilities. Accordingly, paging devices, even highly miniaturized paging devices in the form of a wristwatch, store significantly more paging messages and make available such information for review by the paging device user. Furthermore, paging message content has diversified into a variety of categories. Information subscriptions available through a paging service include, for example, sports information, financial information, weather information, and news information. Also, a paging service can notify the user of new voice mail and electronic mail. Paging devices receiving and storing such rich information content hold a relatively complex database of information ranging from personal paging messages to information in a variety of categories such as financial, sports, weather and the like.
As the storage capability and variety of message type categories increases, the complexity of the data structure holding the stored paging messages necessarily increases. For example, storage of paging messages should take into account the message type. A data structure including "folders" or directories holding messages of a given category helps organize the stored paging messages according to user interest. As the user displays stored paging messages, review of only certain categories of interest at that time, e.g., financial information taken from the financial folder, should be possible without review at that time of unrelated paging messages, e.g., weather information in the weather folder. Also, new or unread paging messages should be available for review separate from previously read paging messages.
Similarly, the task of reviewing such rich information structures becomes more complex, especially in the context of a small electronic device with a limited number of control buttons. A serial list of all stored paging messages and single button operation to move serially through the entire list allows access to the entire list, but quickly becomes unacceptable due to the complexity and diversity of the stored information. Simple control schemes become burdensome or impossible when paging messages are stored in more sophisticated data structures, e.g., structures including "folders" holding categories of paging messages. More sophisticated control schemes taking into account the nature and structure of the stored paging messages are possible, but typically require use of more than one control button, and/or complicated or dynamic control button function assignment. For some applications, joy sticks and multiple control buttons have been used. Other applications have proposed use of four to eight direction buttons and an enter or accept button to navigate through complex data structures. With space so important and limited on small electronic information storage and display devices, it can be hard for the user to tell which button to push and when to push it. Preferably, user navigation or review of complex data structures should be natural and obvious to avoid user confusion and increase user satisfaction.
Generally, an acceptable control scheme must be simple and intuitive, not requiring the user to memorize button function assignments and preferably not requiring the user to manipulate more than a limited, and most preferably only one, control button.
Thus, advancing technology provides significant increase in the amount and type of information available for display in small information display and storage devices, but has not made more simple the user's task in reviewing such information due to the limited number of control buttons available on such small electronic devices. The subject matter of the present invention provides the user an ability to more easily review complex information structures by use of a single control button.